Generally, an automotive sunroof structure comprises an opening provided in the roof of the automobile, a sunroof panel made of either glass or steel plate for closing this opening, and a mechanism for moving the sunroof panel between a retracted or open position and a closed position either by a sliding motion or a tilting motion of the sunroof panel. The mechanism may be driven either manually or by an external power source such as an electric motor. In such a sunroof assembly, the sunroof panel is provided with a seal structure which, when the sunroof is closed, keeps off rain water and so on from the passenger compartment but is additionally provided with a trough which extends along the edge of the roof panel opening and receives water which has passed through the seal structure. This trough is connected to drain hoses which are typically connected to the bottom parts of the corners of the trough.
Conventionally, this trough was provided by press forming a sunroof base panel which supports guide rails and other mechanical parts for accomplishing the motion of the sunroof panel, for instance, as shown in Japanese Utility Model Publication No. 58-27851. Thus, the peripheral fringe of the sunroof base panel is provided with a main part supporting the mechanical parts for moving the sunroof panel, a trough which is depressed in relation with the main part, and an outer upright wall which defines the outer periphery of the trough.
A sunroof panel of this structure is, however, known to have a number of problems. First, the connection between a corner portion of the trough and a drain hose is accomplished by a tube member which is attached to the corner portion of the trough by means of brazing. This brazing process itself and the subsequent finishing processes applied to the brazed part for preventing the rusting thereof and inspecting the soundness of the brazed part significantly increase the manufacturing cost.
Furthermore, since the trough is depressed from the main part of the sunroof base panel, it reduces the head clearance of the passenger compartment when the vehicle height is to remain the same.